Researchers Uncover Data to Help Fight Avian Flu

SPAIN - A team of researchers from the National Research Council (CSIC) has determined the structure of the complex molecular machine that the influenza virus uses to replicate and express their genetic material.

The results, which are published in Science Express, the online edition of the journal Science, opens the way to unravel some of the crucial steps in the life cycle of these viruses that infect birds endemic also to humans and other mammals.

Researchers have revealed ribonucleoproteins organisation, protein complexes formed by each RNA (ribonucleic acid) associated with the viral polymerase and nucleoprotein, multiple copies of which bind to RNA like beads on a necklace.

"This complex structure actually functions as a molecular machine capable of transcribing the genetic message of self-replication of the virus and the infected cell in order to generate new progeny virus to infect other cells," explains Juan Ortin, CSIC researcher at the National Center for Biotechnology.

Scientists have extracted and purified ribonucleoproteins particles and they have been studied by electron microscopy and computer processing.

This methodology has enabled scientists to determine the structure of the insulated ribonucleoproteins through electron tomography techniques on intact viruses and verify that the isolated ribonucleoproteins structure was the same as that found in the virus.

"The final structure shows a double helix organisation with two nucleoprotein and RNA strands. At one end of the double helix is polymerase.

"Furthermore, we have verified that the ribonucleoproteins compact differently when grouped within the intact virus," says investigator Jaime Martín-Benito.

Future prospects

The analysis of the results, together with previously existing data, will reveal some of the crucial steps in the life cycle of the influenza virus, which can cause annual epidemics and occasional pandemics.

"The next step is to examine the mechanisms used ribonucleoproteins to replicate and express the genetic information of the virus and the way in which these are associated with each other in the virus particle," the researchers added.